The invention relates to analog circuits in an integrated circuit environment and, in particular embodiments, to low voltage integrated circuits having both digital and analog components.
As higher levels of circuit integration are achieved more analog functions are being mixed with digital functions on the same integrated circuit. In addition, as circuit dimensions shrink, integrated circuit supply voltages decrease. There is therefore a need in the art for techniques to facilitate the use of lower voltages in mixed integrated circuits.
The invention discloses apparatus for providing an adjustable bandwidth high pass filter while minimizing the effect on signal amplitude. A highpass filter has an input capacitor in series with a resistive ladder. The resistive ladder comprises a plurality of resistors coupled in series. The coupling between the capacitor and the first resistor of the resistive ladder defines a first tap and successive couplings between resistors form successive taps. The last resistor of said resistive ladder is coupled to a ground. A plurality of bandwidth adjusting resistors, each having a first side coupled to the first tap, are included. A plurality of switches, each providing coupling for a second side or a corresponding bandwidth adjusting resistor to said ground are also included.